bufo. 245 



fordshire, Berkshire, Cambridgeshire, Suffolk, Nor- 

 folk, Lincolnshire, Cheshire, Lancashire, Westmor- 

 land, and Cumberland. In Ireland it is only known 

 from the co. Kerry, where it is very abundant around 

 Castlemaine and Valentia harbours. The highest 

 altitudes at which this species has been found are 

 3250 feet in the Alps, and 4000 feet in the Jura. 



In describing the distribution of the common toad, 

 attention has been drawn to its absence from many 

 islands. The present species and the green toad, on 

 the contrary, appear to be found in most of the islands 

 within the area of their habitat, a fact that may bear 

 relation to the greater facility with which the eggs and 

 larvse of both these species can resist salt water. 



Two specimens, male and female, from Mes nil- 

 Saint-Blaise, Belgium, are figured on PI. XIII, the 

 male in the act of croaking, with fully distended gular 

 sac, the female in the running attitude so characteristic 

 of this species. 



Hybrids. — Although no specimens have yet been 

 found in a free state which there is sufficient reason 

 to pronounce as hybrids, it is a well-known fact, 

 tested by de l'lsle, Bruch, Pfliiger, Born, and Heron- 

 Royer, that under artificial fecundation our species 

 of toads cross much more readily than do the frogs. 

 De l'lsle succeeded in obtaining hybrid larva) between 

 Bufo vulgaris and B. calamita, Heron-Royer perfect 

 young of the same, and Born perfect young between 

 B. vulgaris and B. viridis. C. Koch has noticed, 

 under the name of Bufo cinereus, var. hybridus, a 

 female specimen caught near Frankfort (M.) in April, 

 1872, pairing with a B. viridis, and which he assumed, 

 from its general appearance, to be a cross between 

 B. vulgaris and B. viridis. The description given of 

 the specimen is, however, to my mind, by no means 

 convincing as to its hvbricl nature. 



